As is known, a radio receiver, in particular in a multimedia system of a motor vehicle, is able to receive a radio signal, in particular an FM radio signal, FM being the acronym for frequency modulation.
Such an FM radio signal, received in modulated form by a radio receiver, is subjected to various sensors and to suitable filtering so that the corresponding demodulated radio signal is able to be played back under good conditions, in particular in the passenger compartment of a motor vehicle.
Those skilled in the art know the operating principle of an FM, that is to say frequency-modulated, radio signal received by a suitable radio receiver, with a view to being demodulated and then played back to listeners.
One known issue that affects the reception of an FM radio signal via a mobile radio receiver, in particular integrated into a motor vehicle, lies in the fact that the reception of an FM radio signal on a channel may be subject to interference through the presence of another separate FM radio signal on the same channel.
When this occurs, more often than not due to an incorrectly defined frequency plan, two or even more radio signals may be received by a radio receiver.
To detect the presence of co-channel interference, the prior art does not disclose any dedicated sensor. The presence of co-channel interference is thus inferred, in the prior art, by way of interpreting information from existing sensors: signal level sensor, multipath detector (typically corresponding to a sensor for sensing the presence of an amplitude modulation of the signal when the radio receiver under consideration is an FM receiver), and noise sensor.
In the prior art, it is known to combine this information, via a more or less complex matrix, in order to determine a probability that co-channel interference is currently present.
For example, if an amplitude modulation is detected in the reception of an FM radio signal, then the presence of multipath interference or co-channel interference may be deduced.
Document U.S. Pat. No. 8,064,857, incorporated herein by reference, describes one example of such a technique.
These probabilistic estimations implemented in the prior art do not make it possible to determine with a high level of confidence whether or not co-channel interference exists.
However, this determination is important in order to allow the radio receiver under consideration to implement optimum signal processing in order to attenuate or even remove the current interference.